Patent attributes
With a first endoscope inserted through an overtube, the overtube is orally inserted into an object being examined, and a distal end portion of an insertion tube of the first endoscope is made to advance, within the object, from a jejunum via a jejunum-to-jejunum anastomosed portion and a jejunum-anastomosed bent portion so that the distal end portion is located adjacently to a Vater's papilla of a duodenum. The overtube is then sent to a position which is adjacent to the Vater's papilla along the insertion tube of the first endoscope. After this, the first endoscope is pulled from the overtube. A second endoscope is then inserted into the overtube to make a distal end portion of its insertion tube protrude from the distal end of the overtube and is located adjacently to the Vater's papilla. The second endoscope thus-approached is used to treat the Vater's papilla and the tissue therearound.